CMake: Allow build tree to be used as a pseudo-install-tree

Once JUCE has been built, you can use the following line to include
the targets from the build tree (replace `JUCE_BUILD_DIR` as
appropriate).
```
include("${JUCE_BUILD_DIR}/JUCEExportConfig.cmake")
```

CMakeLists.txt

@@ -80,11 +80,24 @@ set(JUCE_INSTALL_DESTINATION "lib/cmake/JUCE-${JUCE_VERSION}" CACHE STRING
     "The location, relative to the install prefix, where the JUCE config file will be installed")
 
 install(EXPORT JUCE NAMESPACE juce:: DESTINATION "${JUCE_INSTALL_DESTINATION}")
-
+set(JUCE_EXPORT_FILE_NAME "JUCE.cmake")
+set(UTILS_INSTALL_DIR "${JUCE_INSTALL_DESTINATION}")
+set(JUCEAIDE_PATH "${JUCE_TOOL_INSTALL_DIR}/${JUCE_JUCEAIDE_NAME}")
 configure_package_config_file("${JUCE_CMAKE_UTILS_DIR}/JUCEConfig.cmake.in"
     "${JUCE_BINARY_DIR}/JUCEConfig.cmake"
+    PATH_VARS UTILS_INSTALL_DIR JUCEAIDE_PATH
     INSTALL_DESTINATION "${JUCE_INSTALL_DESTINATION}")
 
+set(JUCE_EXPORT_FILE_NAME "JUCEBuildTree.cmake")
+export(EXPORT JUCE NAMESPACE juce:: FILE "${JUCE_EXPORT_FILE_NAME}")
+set(UTILS_INSTALL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/extras/Build/CMake")
+get_target_property(JUCEAIDE_PATH juceaide IMPORTED_LOCATION)
+configure_package_config_file("${JUCE_CMAKE_UTILS_DIR}/JUCEConfig.cmake.in"
+    "${JUCE_BINARY_DIR}/JUCEExportConfig.cmake"
+    PATH_VARS UTILS_INSTALL_DIR JUCEAIDE_PATH
+    INSTALL_PREFIX "${CMAKE_CURRENT_BINARY_DIR}"
+    INSTALL_DESTINATION "${CMAKE_CURRENT_BINARY_DIR}")
+
 install(FILES "${JUCE_BINARY_DIR}/JUCEConfigVersion.cmake"
               "${JUCE_BINARY_DIR}/JUCEConfig.cmake"
               "${JUCE_CMAKE_UTILS_DIR}/LaunchScreen.storyboard"

extras/Build/CMake/JUCEConfig.cmake.in

@@ -20,24 +20,14 @@
 
 @PACKAGE_INIT@
 
-include("${CMAKE_CURRENT_LIST_DIR}/JUCE.cmake")
-
-get_filename_component(_IMPORT_PREFIX "${CMAKE_CURRENT_LIST_FILE}" PATH)
-get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
-get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
-get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
-if(_IMPORT_PREFIX STREQUAL "/")
-    set(_IMPORT_PREFIX "")
-endif()
+include("${CMAKE_CURRENT_LIST_DIR}/@JUCE_EXPORT_FILE_NAME@")
 
 if(NOT TARGET juce::juceaide)
     add_executable(juce::juceaide IMPORTED)
     set_target_properties(juce::juceaide PROPERTIES
-        IMPORTED_LOCATION "${_IMPORT_PREFIX}/@JUCE_CMAKE_BINARY_BUILDER_NAME@")
+        IMPORTED_LOCATION "@PACKAGE_JUCEAIDE_PATH@")
 endif()
 
-set(_IMPORT_PREFIX)
-
 check_required_components("@PROJECT_NAME@")
 
-include("${CMAKE_CURRENT_LIST_DIR}/JUCEUtils.cmake")
+include("@PACKAGE_UTILS_INSTALL_DIR@/JUCEUtils.cmake")

extras/Build/juceaide/CMakeLists.txt

@@ -85,6 +85,5 @@ else()
     install(PROGRAMS "${imported_location}" DESTINATION "${JUCE_TOOL_INSTALL_DIR}")
 
     get_filename_component(binary_name "${imported_location}" NAME)
-    set(JUCE_CMAKE_BINARY_BUILDER_NAME "${JUCE_TOOL_INSTALL_DIR}/${binary_name}"
-        CACHE INTERNAL "The name of the juceaide program")
+    set(JUCE_JUCEAIDE_NAME "${binary_name}" CACHE INTERNAL "The name of the juceaide program")
 endif()